MEWAPREV Résumé de rapport

Supported Liquid Membranes (SLM)

This new technology has received considerable attention during the last decade. The SLM results and technology in the Mewaprev project are built on those achieved in the earlier Sereni project.

The SLM-technique consists of a combined extraction and stripping process. Both process steps occur simultaneously at the interface of a membrane.

The key to this technique is the development of a selective extractant (carrier) which is immobilised in an organic membrane. This carrier enhances the transfer rate and can be selective.

The metal ion in the aqueous phase reacts with the extractant to a complex which diffuses through the membrane and is extracted by an auxiliary component in the strip phase. This mechanism enables the metal ions to be removed in the outer water phase (rinse waters, spent plating solutions down to less than 0.5 ppm or less and concentrated in the inner phase (strip phase) up to several g/l. This technique can be developed to a continuous process for metal salts recovery.

In contrast to the alternative environmental techniques, the PARCOM values can be reached with the Supported Liquid Membrane technique.